Method and device for generating, merging and updating of destination tracking data

ABSTRACT

A method and device for generating, merging and updating data for use in a destination tracking system which comprises, among others, the following steps: Generation of data by mobile units (vehicles) to model reality concerning route(s) and traffic, and storing this data for further use. A highly up-to-date and extremely reliable database is built-up in a simple and efficient way by merging data from many units. This database makes it possible to answer a number of complex problems, for example, about the passable route network and realizable travel times. On input of an origin and a destination node together with the intended travel time, destination tracking data is calculated from the stored data. Since the origin-destination relationships of the motions carried out by the mobile units in dependency of all conceivable parameters are known, the destination tracking recommendations for each individual participant can be given such that the sum of the times of movement of all participants is minimized.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a method for generating and updating data foruse in a destination-tracking system consisting of at least one mobileunit in accordance with claim 1 as well as a device for carrying thisout in accordance with claim 38.

2. Description of the Related Art Including Information Disclosed Under37 CFR 1.97 and 1.98

Navigational or destination tracking systems have recently beenattracting significant attention, particularly their application inmotor vehicles. The purpose of such systems lies in guiding a driver toa target destination by electronic aids after the destination has beenentered by the driver. Firstly, the route can be found accuratelywithout tiresome questioning of third parties and secondly, congestionor other traffic obstructions can be avoided.

Typical navigational systems work by continuously analyzing the currentlocation of a moving vehicle and comparing this position with a roadnetwork in the form of geographical data. This information can be readfrom a road map stored, for example, on a CD-ROM carried in the vehicle.From the geographical data and assumptions about achievable speeds, acomputer determines a favorable way to a destination possibly oroptionally taking into account additional specific road information suchas reports of road works, accident reports, etc., transmitted bycommunication systems. The result is shown by means of a display, forexample represented graphically in the form of a map, in which thelocation of the vehicle is indicated, e.g., by a point. On the basis ofthe map displayed together with the current location of the vehicle, thedriver can follow the displayed route up to the destination node. Such asystem or method is described, for example, in DE 35 12 127 A1.

Similarly, DE 38 28 725 A1 describes a method to record and store aroute carried out for the first time with a facility installed in thesubject vehicle. When making a new trip along the same route, thisrecorded information can be reused. This method is intended to simplifythe requirements, described in DE 35 12 127 A1, of comparing the currentlocation of the vehicle with stored geographical data for a route whichis already known to the subject vehicle. DE 41 05 180 A1 describes anautonomous road guiding system for motor vehicles which contains adevice to record the course of a street actually taken and stores thedata in a storage unit. Impulses along the route are detectedautomatically, whereas changes of direction are entered by hand via thepush-buttons of the device or via the direction indicator of thevehicle. The storage unit thus programmed can be taken out of the deviceand given to a third party thus making it possible for the third partyto drive along an unknown route with the help of the storage unit. Oneof the problems of this autonomous road guiding system, among others, isthat only quite specific road topologies can be saved and updates arenot carried out. Thus neither changes in the road topology norunexpected events between the programming of the storage unit and thetrip of the third party are taken into account. Additional problems areencountered in the “calibration” of the geographical data.

In addition to the above, DE 40 08 460 A1 describes a method which takesinto account the current traffic conditions when selecting a route. Thecurrent traffic condition data is transmitted to the destinationtracking device in the vehicle in the same way which makes it nowpossible for vehicles with radio sets to receive radio traffic news.

DE 43 34 886 A1 describes a destination tracking device for motorvehicles with an on-board computer which extracts and processes signalsfor a route to a given trip destination said to be optimal with regardto travel time and/or fuel consumption. The vehicle contains a facilitywhich has collected and stored data on the time-dependent occurrence oftraffic obstructions during at least one earlier information gatheringtrip. Said data are entered into an on-board computer and taken intoaccount when determining a modified route. The well known destinationtracking device mentioned above has the advantage that it is notdependent on external facilities such as radio traffic services orcomputers to record traffic hold-ups. However the data entered toidentify traffic obstructions is seldom up to date. The geometric routesection data, furthermore, is taken automatically from a CD-ROM andconsequently is not always up to date.

U.S. Pat. No. 4,350,970 A1 describes a method for recording the traveltime of a vehicle between two given nodes, and for transmitting saidtravel times to a computer designated as the master computer. Saidmaster computer then compares the travel times with average values; ifthere are significant deviations, another route is proposed tosubsequent vehicles. The transmitting vehicle does not receive therevised result. In other words it is a traffic control system and not adestination tracking system.

DE 195 26 148 C2 and DE 195 34 589 A1 describe methods as well assystems for forecasting traffic flows. The basic structure correspondsto the method and system discussed earlier in DE 35 12 127 A1. But incontrast to the method and system disclosed in DE 35 12 127 A1, themethod and system described in DE 195 26 148 C2 successively stores themomentary vehicle speed and its current position which are continuouslydetermined by means of a receiver tracking signals from a navigationalsatellite system, said receiver being located in a storage unit in eachvehicle of a sampling fleet. The stored locations are part of the triproute data which are transmitted time-dependently and/orroute-dependently by the sampling vehicle to a traffic control computer.Simultaneously “current trip activity data” from stationary sensors isalso transmitted to the central computer. The central computer thenanalyses the transmitted route and trip activity data against a storeddigital road map and determines the traffic volumes, i.e. the vehiclesper time unit at a specific road cross section based on that route data.Subsequently, according to DE 195 34 589 A1, traffic development can beforecast by the central computer from the stored traffic volumes. It isreported that the central computer can propose “time-optimal” routes toother road users based on this forecast and its stored digital roadmaps. The title of DE 195 26 148 C2 not withstanding, traffic flowscannot be forecast by these known methods or systems since the mostimportant information requirement, namely the start and destinationnodes of the vehicles, are not known by the central computer.Furthermore, the corresponding linear equation system always exhibits anarbitrary degree of incorrectness.

The systems or methods described in DE 35 12 127 A1, DE 38 28 725 A1 ,DE 40 08 460 A1, DE 195 26 148 C2 and DE 195 34 589 A1 have one thing incommon, they all use a static database with regard to the geographicaldata. An exchange of the geographical data is carried out only from timeto time. Even a short time after the geographical data of a certainregion has been fed into the storage device of a vehicle, it may nolonger be up to date since, for instance, a route or link may beblocked, or newly opened, or the travel direction in a one-way streetmay have changed. Furthermore, these known systems or methods do nottake into account the fact that the same route may exhibit differenttravel times at different times of day, traffic conditions, weatherconditions, etc. Another inherent property of these conventional systemsis that the destination is addressed by input of the name of thelocation together with the name of the road and, sometimes, a streetnumber. If the destination node in this format is not known to thesystem it is impossible to calculate any route.

Furthermore, these known methods and systems are based on the hypothesisthat the available road network is essentially known. In fact, however,the geographical data actually stored represents reality onlyincompletely, with the degree of incompleteness varying from region toregion.

The effort necessary to maintain updated information on the accessibleroute network is both highly time consuming and costly. It is also notfeasible to operate in all parts of the world with the same standard.Updating of data is always incomplete and prone to errors and can becarried out only after a significant delay in time. The updated data canbe made available to the user only after a significant delay in time.

Since the known methods and systems only have subsets of the actualroute network available, the route recommendations might involveconsiderable detours (with respect to length and time). If for example,an apparently unimportant part of the road network, particularly if itlies in the direct direction to the destination node, is unknown to thesystem, it may cause a significant delay to the vehicle requesting aroute recommendation.

The effect of driving along detours can easily take on considerablesignificance considering that this fault applies to all mobile units.

BRIEF SUMMARY OF THE INVENTION

It is an object of the invention to establish a method to generateappropriate data utilizable for a practical destination tracking systemwhich carries out a permanent self updating and with data generationwhich requires little effort. The method is also appropriate forderiving destination tracking data from the data generated in accordancewith the aforesaid method.

It is another object of the invention to provide a device for carryingout the method described above.

As far as the method is concerned, the object of the invention isattained by the characteristics of claim 1. Additional advantagesresulting from the method of the invention are specified in dependentclaims 2 to 37.

The method of the invention is characterized by the fact that in amobile unit, e.g. a motor vehicle, traveled distance data are generatedand are used for automatically generating a digital route network whichmaps the sections of the route that the mobile unit has covered. Thisnetwork information is then saved in a storage device. This routenetwork is stored as a section data file which contains the individualroute sections with their initial and end points. By means of thecontinuous extension and/or updating of the section data file with newsection data generated for new sections traveled by the mobile unit, theroute network corresponds, step by step, to the conditions of the realroute network so that, at any point in time, there is a current routesection network available to the mobile unit.

In addition to the geographical coordinates x_(i), y_(i), of the pointsP_(i), the direction of movement ∝_(i) of the mobile unit can berecorded when generating the traveled distance data. The direction ofmovement ∝_(i) can either be derived from the geographical coordinatesx_(i), y_(i), of the points P_(i) of the traveled distance data or bedetected by means of at least one sensor unit provided for the mobileunit.

To avoid unnecessary overburdening the storage device provided in themobile unit, additional provisions can be made to permit the generationof traveled distance data and/or section data to be interrupted if thenewly generated data already exist in the storage device of the mobileunit, and to cause said generation to be restarted if the newlygenerated data have not yet been stored in the storage device of themobile unit.

Since the section data file stored in the mobile unit is continuouslyextended and/or updated, a highly topical route recommendation can bepresented, at any time, if so requested by entering a desired point ofdestination and possibly a starting point for the mobile unit into aninput device contained therein, provided the mobile unit contains a dataprocessing device. If the starting point is already known, it does notneed to be entered. The suggested route is presented visually and/oracoustically.

The provision of at least one central computer, separate from the atleast one mobile unit, as set out in claim 7, makes it possible to mergethe section data files created by several mobile units into at least oneoverall route file which gives a complete view of the utilizable andused road network. In order to keep the required storage capacity of thecentral computer to a minimum, provisions can be made so that a centralcomputer checks a section data file transmitted by a mobile unit for itsupdate value before merging the new section data files and only mergesthose section data files which have been recognized as at leastpartially new into the overall route file. According to thecharacteristics of claim 9, it is possible to build up different overallroute files for different types of mobile units, for example specialfiles for cars, lorries, motorcycles, cars of various size or type ofmotor, etc. Other criteria, attached for example to the user of themobile unit (age, sex, etc.), can also be taken into account for theconstruction of various types of overall route files. Such type specificfiles permit the selection of the most favorable route for each categoryof users.

According to the method of the invention, data collection is fullyautomatic. Collection of data can of course be switched off from withinthe mobile unit. If the individual participants are hesitant to havetheir personal data transmitted to a central computer, then according toclaim 10, it may be advantageous to pay for data transmitted byparticipant to a central computer in order to achieve optimal datacollection. The amount of the reimbursement fee can be determined inaccordance with the update value of the data.

The communication between the mobile unit and a central computer can beachieved in various ways. The data recorded by the mobile unit can betransmitted to the central computer automatically upon reaching the endof a movement, for example defined as reaching the point of destination,or if requested by the central computer either periodically or inaccordance with any other criterion. Given that a mobile unit is fittedwith adequate devices, communication between a central computer and amobile unit can occur alternatively automatically, after a given timeperiod, or upon request by the mobile unit, as a function of the updatevalue of the item of new information to be transmitted, or in accordancewith other criteria.

Besides an optional processing device in the mobile unit, a centralcomputer can also propose and transmit to a mobile unit, if so requestedby said mobile unit specifying a starting point and a destination point,a proposed route on the basis of the at least one overall route filealready stored in the central computer.

Frequently the existing section data file and/or overall route file doesnot contain the desired origin and/or destination point requested by themobile unit. In such case, to compute a proposed route, it isrecommended that an optional data processing device in the mobile unitor a central computer use the nearest known origin and/or destinationpoint from the section data file stored in the mobile unit or from theat least one available overall route file stored in the centralcomputer.

Known destination tracking systems or methods, in most cases, determinethe requested destination node by inputting the town's name, the name ofthe street, and possibly the street number. However, if the destinationnode is given by its geographical coordinates, it is possible, asalready discussed above, that an optional data processing unit in themobile unit itself, or a the central computer can direct the mobile unitto a destination in close vicinity of the unknown destination node, byusing known coordinates and their corresponding streets and/or streetnumbers. Any available (geophysical) system of coordinates can be usedfor this purpose.

Since the input of coordinates is difficult for the average user of suchnavigational systems or methods, the provision of a bar code reader asan input device to read the coordinates could facilitate the entry ofdata. A voice input is also possible.

In this connection, it should be noted that the destination point neednot be specified by its geographical location alone but also byadditional characteristics. Thus the method of the invention can also beused, e.g., to find routes to supermarkets, exhibitions, amusementparks, etc., and, for example, even a specific exhibition stand on theground of a trade fair could be found. It goes without saying thatdestination data can also be merged with additional data from otherinformation systems, e.g. informative data about the destination such ashotel data, public transport time tables, speed limits, etc.

A further measure to reduce the requirements of storage capacity in themobile unit or a central computer is described in claim 20, according towhich the generation of traveled distance data of the mobile unit isonly activated if the mobile unit does not take the route suggested by acentral computer or by the data processing device in the mobile unititself. Additionally, provision can be made to interrupt the generationof traveled distance data if the trip is interrupted.

Besides the provision explained above for recording geographicalcoordinates x_(i), y_(i), of the points P_(i) of the traveled distancedata, the point in time T_(i) when points P_(i) are reached can also berecorded and stored in the storage device of the mobile unit.Furthermore, provision can be made to assign the absolute time ofmovement T_(jk) to the sections P_(j)P_(k) traveled. Also the actualduration of travel t_(jk) can be assigned to the sections P_(j)P_(k). Bythis means, the realized travel time for each individual section can betaken into account in the planning of a route. This procedure issuperior to that of known technologies which assign the average speedsreached by a traffic flow on a route section or calculate travel time onthe basis of the momentary speed of a sample vehicle, since using speedsto determine a recommended route with a view to the shortest travel timeis inadequate both at the microscopic (one mobile unit) and themacroscopic level. Using recorded speeds (the quotient of distance andtime) to calculate the required travel time for a route section isfundamentally inaccurate since the speed is constantly changing.

A description follows below on how the additional data mentioned abovepermit to build up a section data file and/or an overall route file,which takes into account the patterns of movement at various times onthe same route sections. For the purpose of data compression and theproduction of data which are as meaningful as possible, the points oftime T_(i) can be used to merge the section data for those calendartimes which exhibit a similar typical movement pattern or trafficactivity. This then can be taken into account in the planning of routes.

In addition, it has proven to be advantageous, if the same geographicalsections, when covered during different trips of the mobile units inpredetermined time periods resulting in the duration of movement t_(jk),are combined in the section data file so that, for instance, thedurations of movement t_(jk), are combined in the section data file sothat, for instance, the durations of movement t_(jk) required for agiven section at a given hour on the first Monday of a given month canbe fetched. Average values can be calculated from the durations ofmovement t_(jk.)

The characteristics of claim 28 mean that it is possible to forecast therealizable duration of motion for a typical pattern of movement providedthat no special or unusual events, such as accidents, floods, buildingworks, etc., are present.

In determining the pure duration of motion t_(jk), it may beadvantageous to suppress the idle time of the mobile unit during thecollection of data.

claim 30 gives an example where similar traffic conditions occur duringrecurrent calendar periods. Generally it can be stated that trafficactivity fluctuates periodically so that there are similar calendartimes regarding the traffic activity, e.g., Monday morning, Fridayafternoon, the start of holiday, etc. The features of claim 31 achievethe advantage that, in addition to the section data collected over along period of time and evaluated statistically, the most recent sectiondata are stored in a short-term section data file so that it is possibleto recognize when a special event, such as a particularly slow travelspeed caused by a building works, or an accident, or if the currentsection is part of a one-way road, etc., is present. The nodesP_(J)P_(K) of a route section P_(j), P_(k) can be fixed in manydifferent ways. They can, for example, be fixed according to theoccurrence of changes of direction or because they lie at theintersection points of sections of different direction.

In order, for example, to be able to obtain further information aboutpetrol/gas stations for mobile units, provision can be made to storeadditional information, such as the idle time intervals of the mobileunits, in the section data. claim 36 characterizes the fundamentalexecution of the method for the solution of the second part of thepurpose of the invention. For example, the section file, which modelsthe total traffic activity, permits to calculate, reliably and with ahigh level of topicality, a route from a given starting point to a givenpoint of destination, thus minimizing the duration of motion or thelength of the route.

The features of claim 37 make additional improvements to the precisionof the method in generating destination tracking data. generatingdestination tracking data.

The computer cited in claims 36 and 37 could either be a data processingdevice in the mobile unit or a central computer.

Concerning the device and/or the system, the above object of generatingdata usable for a destination tracking system is attained using thecharacteristics of claim 38. Claims 39 to 52 describe advantageousembodiments of the device of the invention. The device of the inventionhas the same advantages which have been previously explained in thedescription of the method of the invention.

To facilitate inputting address information, an input device can beprovided that reads address information from a data storage medium. Thisdata carrier can, for example, be a visiting card containing the addressinformation. Said facility can also be a bar code reading device or aspeech input device.

It should be noted that the term “mobile unit” covers not only vehiclesbut also, for example, pedestrians who are equipped with a portablenavigational system in accordance with the invention. Such a systemcould be advantageous, for example, to a pedestrian, if the names ofroads in a city are not available or if the names are written incharacters which are not decipherable by the user of the system.

If the mobile unit is a motor driven mobile unit such as a motor car,then the evaluation of the recorded basic data can be improved if therecording unit also includes means for registering the motor revolutionsand the fill level of the storage unit for the energy utilized by theengine of the mobile unit, in particular the petrol tank, and forrecording the temperature and/or humidity, etc. The accuracy of theevaluation of the data can be further improved by these means since themotor revolutions can be used as an indication of how often the vehiclehad to halt at traffic lights and the level of the tank contents can beused to determine where a suitable petrol station is available since thetank's state between empty and full is recorded.

A gyrometer or a compass can be provided to register the direction ofmovement of the mobile unit. The device for recording the respectiveabsolute position might also be a GPS receiver. In order to reduce theamounts of data required by a central processing unit for thefulfillment of its tasks, it can be advantageous to connect severalregional stationary central computers in a network instead of installinga single stationary central computer.

Summarizing, the travel destination tracking data can be calculated fromthe overall route file after the input of both origin and destinationnodes as well as the intended travel time. Since all origin-destinationrelationships of the traffic or the actual movements of the mobile unitsin relationship to all possible parameters are known, it is possible togive destination route recommendations for all traffic participants insuch a way that the sum of time for the movements of all participants isminimal.

Further advantageous embodiments as well as a demonstration by exampleare explained below with reference to the following figures:

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a block diagram of an on-board system in accordance with theinvention for a vehicle operating as a mobile unit;

FIG. 2 is a block diagram of a computer which communicates with thesystem in accordance with FIG. 1;

FIG. 3 is a schematic representation of a road network with nodes 1 to16 representing road intersections with the lines connecting the nodesrepresenting roads;

FIG. 4 is a schematic representation of the network of FIG. 3 showingtwo possible routes between points 1 and 16;

FIG. 5 is a schematic representation of a known road network with adestination point Z outside the network;

FIG. 6 is a schematic representation of the road network of FIG. 5 afterthe destination Z has been reached;

FIG. 7 is a schematic representation of the network of FIG. 6 with theaddition of a starting node S outside the known network;

FIG. 8 is a schematic representation of the network of FIG. 7 with theaddition of the connection of node 18 to node 2;

FIG. 9 is a schematic representation of the network of FIG. 8 with theaddition of an intermediate node 19 outside the network; and

FIG. 10 is the schematic representation of a final network after amobile unit has traveled a route including nodes 18, 19 and 17.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates the destination tracking system in accordance withthe invention with its two essential assemblies. The destinationtracking system can be installed in a vehicle operating as a mobileunit. In FIG. 1, the inputs of an electronic control device, orelectronic unit, designated as a whole with reference number 2 areconnected to the sensors, or signaling devices, mentioned below.

A navigational GPS (global positioning system) receiver 4 produces datawhich give the geographical position of the control device 2 of themobile unit by, for instance, geographical latitude and longitude.Optionally, the altitude can also be given.

A compass 6 containing, for example, two cross coils reads thegeomagnetic field. The compass, which is compensated with regard to anymagnetic declination due to the control device 2 or the vehicle,produces a signal ∝ which corresponds to the direction of the mobileunit or the vehicle relative to the magnetic north. The compass 6 can besupplemented or replaced by a gyroscope which delivers a more exactvalue of the direction because of its gyro-stabilization.

A mileometer 8 generates an impulse for each unit of distance covered.This can be done, for example, by reading the revolutions of thevehicle's wheels. Unit 10 is a clock which generates a signalcorresponding to the absolute time.

A vehicle signal generator 12 generates a signal specific to eachvehicle type. This device is permanently programmed upon installation inthe vehicle. An event manager 14 generates a specific signalcorresponding to the occurrence of a specific event: i.e. opening and/orclosing a door; refueling (opening the petrol tank cap, changing thefuel level); vehicle maintenance (resetting the maintenance intervalmonitoring device); rain (continuous use of the wipers); frost (lowoutside temperature); etc. It is understood that additional signalingdevices can be made available to record, for instance, fine weather(sunshine), the load under which the engine runs, the weight of thevehicle, the axle loads, etc. In particular, measuring the axle loadingis a very simple but most effective method for calculating the stress onthe road surface at a road cross section by summing the axle crossingsor the normalized axle crossings. The data, when made available to acentral computer, can be evaluated to determine the point in time whenthe road surface requires renewal.

The control device 2 also contains an interface 20 to convert the outputsignals of devices 4 to 14 into digital signals that are then processedwithin device 2; a micro processor 22 executing several differentcomputational procedures; a ROM 24, which, among other things, containsthe working programs for the micro processor 22; and a RAM 26 withdirect access into which the information and current data required toexecute the programs are written and from which said information is readout.

An input unit 28 is provided to feed the control device 2 with data. Anoutput or display unit 30 can output information acoustically and/oroptically. A data input/output device 32 is provided so that the controldevice 2 can transmit data to and receive data from a remote centralcomputer. The data input-output device 32 can send or receive datadirectly or by modem. It can also contain a portable data carrier, bymeans of which data can be read or written into another location, forexample by means of a personal computer (PC). Data can also be inputtedand outputted via sensors built into the mobile units and communicatingwith stationary sensor devices located, for example, in parking lots,petrol stations, etc., said sensors operating either ultrasonically, inthe infrared spectrum, or any other non-contact or wireless method.

The data which is derived from signals generated by the devices 4 to 14are evaluated and stored in a trip storage unit or motion storage unit40, respectively, a section data storage unit 42, a section data filestorage unit 44, a short-term storage unit 46 and an event storage unit48. The function and the contents of the storage units named above areexplained in detail below.

The storage units named above are connected by a data bus 50. Theconstruction of these units is well known and does not need to befurther described here.

FIG. 2 shows the circuit diagram of the central computer 62, which hasmany components which are similar to those of the control device 2 withwhich it communicates directly or indirectly over a transmission device64. In the total system, several central computers connected in anetwork can be assigned different tasks.

The central computer 62 contains a microprocessor 66 with a ROM 68, anda RAM 70, an overall route file storage unit 72, a short-term storageunit 74, and an event storage unit 76. An input/output device 78transmits data to and from the central computer 62. The construction ofall of these constituent units, connected over a data bus 80, is wellknown.

A typical working sequence of the devices described above is outlinedbelow: When a vehicle representing a mobile unit and equipped with thesystem corresponding to FIG. 1, activated via input unit 28, is started,the GPS receiver 4 sends a signal which identifies the location of thevehicle, compass 6 sends a direction signal ∝, and clock 10 sends a timesignal t. These three signals are combined, in the trip storage unit 40,to a first traveled distance data P_(i) comprising the geographicalcoordinates x_(i), y_(i) of the starting point P_(i) and the absolutetime T_(i). The subsequent points P_(i+1), . . . , P_(i+n) are stored inthe same manner according to a prescribed routine, for example, after agiven time interval given by the clock 10 or after a certain distancehas been covered as given by the mileometer 8. The location coordinatesx and y are compared for plausibility with the subsequent pointscalculated on the basis of the direction signal ∝ and the time signal t,and any deviations are averaged. Thus the route covered is recorded by aseries of points. The point records can be supplemented by datagenerated by the vehicle type signal unit 12, said data way includevehicle model and type, motorization, or similar information mentionedabove. If the event generator 14 produces a signal, e.g. a refuelingsignal, this signal is stored as an event signal E, in the event storageunit 48 together with the location x_(i), y_(i) and the time T_(i). Ifthe vehicle is not moving and this stationary period matches an eventsuch as opening and/or closing a door, refueling, etc., then this isjudged to be an interruption of the trip. The points of a first routeending before the event and of the further route traveled subsequent tothe event are stored in the trip storage unit 40.

After completion of a trip or even during the trip, section data aregenerated from the traveled distance or route data stored in the tripstorage unit 40, compressing the traveled distance data by droppingindividual points P_(i) and choosing those points P_(j) and P_(k) whichare most by dropping individual points P_(i) and choosing those pointsP_(j) and P_(k) which are most characteristic in defining a section ofthe route. For example, characteristic route nodes P_(j) and P_(k) arenodes where the vehicle direction ∝_(i) changes by more than a givenpredetermined value, or nodes at the intersection of sections orientedin different directions, or nodes that are otherwise conspicuous. Thesections P_(j)P_(k) calculated from the route nodes P_(i) stored in thetrip store are saved in the section data storage unit 42 in thefollowing manner:

P_(j)P_(k) =x_(j), y_(j), x_(k), y_(k), t_(jk), and T_(jk), where x andy represent the geographical coordinates, t_(jk) is the time required tomove between the points j and k and T_(jk) is the absolute time of thetrip along the section P_(j)P_(k) . Thus a large number of section dataP_(j)P_(k) are saved in the section data storage unit 42, said sectiondata being compacted in comparison to the total number of nodes P_(i)passed on the trip since at least some of the sections include more thantwo nodes P_(i).

The numerous trips carried out by a vehicle, whereby the same section isnormally traveled several times, are further compressed in the sectiondata file storage unit 44. In the section data file storage unit, theabsolute time is divided into a number of fields A_(i) relating tospecific traffic conditions. Each A_(i) stands for a specific timeperiod, for instance, a particular day in a given month, i.e. it definesa traffic relevant time period. Traffic relevant time periods are, forexample, periods when particularly strong rush-hour traffic occurs everyMonday morning or, in states which celebrate Christmas from December24th to 26th, periods when especially heavy long distance holidaytraffic occurs each year on December 27th on certain routes. TheThursday before Easter is an example of a holiday not connected to afixed date which is linked to special traffic conditions. Based on thedurations t_(jk) and the absolute times T_(jk), during which certainsections P_(j)P_(k) are traveled, a check routine of the microprocessor22 can independently determine characteristic periodicities or eventsand define corresponding traffic relevant time periods A_(i).

The sections P_(j)P_(k) with the corresponding durations t_(jk) and thefrequency distribution h (t_(jk)) are saved in the section data filestorage unit. Thus the section data file storage unit contains a sectiondata file which in turn contains the expected time t_(jk) required totraverse a section P_(j)P_(k) grouped by traffic relevant time periodsA_(i).

The more section data are assigned to a traffic relevant time period inthe section data file storage unit, the more significant is the expectedtrip time in normal traffic conditions. This precision seems useless ifa sudden event changes the traversability of a section P_(j)P_(k). Inorder to take into account such special cases, the section data from thesection data storage unit 42 are stored in the short-term storage unit46 for a short period of time, for example the last 24 hours.

The events E_(i) reported by the event generator 14 are saved in theevent storage unit 48 together with the coordinates x_(i), y_(i), andthe point in time T_(i) at which the event occurred. In this way, alltrips carried out by the respective vehicle are saved in the controldevice 2 in the form of sections together with the associated trip timeand the traffic relevant points in time. It is self evident that thegeometric data of the sections, in so far as they are not new, are notre-recorded on each trip. Thus usually only the duration of the trip andthe absolute time and/or the traffic relevant point in time areregistered. The user can, of course, switch off the recording and/ortransmission of data at any time.

In order to merge the trips of a large number of vehicles and thusachieve an even more significant and extensive coverage of data, thedata saved in the storage units 44, 46, and 48 of the specific controldevice 2 of the vehicle are transmitted, either automatically after agiven period, or on request by entry in the unit 28, by the datainput/output device 32 to the central computer 62. This datatransmission can be either a wireless transmission from the vehicle, bycable using a data carrier taken from the vehicle, or in any other way.Thus it can take place during the trip, or when the vehicle stops, i.e.in a car park, garage, filling station etc. Data transmission can betriggered automatically after a given period, or coverage of a certaindistance, depending on the update value of the data, or on request froma central computer, or in some other way. The data from differentvehicles is merged in the section data file storage unit 72, theshort-term storage unit 74, and the event storage unit 76 and saved, ifrequired, in accordance with the specific vehicle class (vehicle signalgenerator 12). If, on data transmission to the central computer 62,additional vehicle identification data (vehicle signal generator 12) isdelivered, the central computer 62 can evaluate the information contentand/or the update value of the transmitted data and transfer acorresponding credit note to the sending vehicle. Alternatively, a tollaccount can also be carried out by the central computer.

Ensuring that the one (or more) central computer(s) of the system havecontinuous full coverage of relevant data is achieved as follows: Thecomputer of every vehicle recognizes the update value of the data whichit has just determined with regard to the geometric contents (traveleddistances) and time contents (trip times). This update value (e.g. theamount of new data) is offered to the central computer together with ageographical specification (e.g. the geographic center). If the centralcomputer requests the data, then a credit note is promised if the datais sent immediately.

A central computer makes a direct inquiry to vehicles currently in areasfor which a data requirement exist. A central computer knows thelocations of the vehicles because of their past requests for data ordata transmission. A central computer can alternatively request vehiclesin the area of interest directly by sending the geometric data of thetarget area. The vehicles then compare the transmitted data with theirown location data.

A continuously updated file, more or less condensed, depending on theevaluation procedure, is built up in the central computer 62, andrepresents the complete traffic activity within the area covered. Thisinformation can be evaluated for highly specific tasks by planningauthorities, maintenance authorities, etc. Since the data is verycomprehensive and up to date it can be used for problems such as greenwave traffic signals, one-way traffic, etc. The control of green wavetraffic systems require a detailed knowledge of the location of trafficlights, signal time plans, and of the relevant traffic flows. All ofthis information is contained in merged data received from individualvehicles. Given knowledge of traffic light location and time phases, theindividual vehicle can receive a recommendation on speed so that theprobability of a stop free journey is maximized.

The entire system requires no infrastructure such as signal coils in thestreets, central storage of the road network for example in CD-ROM,collection of traffic statistics, etc., although the use of a CD-ROM asan initial data set is not excluded. The above description deals withthe system as far as it is used to generate data via signaling units 4to 14 contained in individual vehicles (see FIG. 1), which data can beused for a destination tracking system.

The following description explains the use of the system for derivingtracking data from the generated data.

It is assumed that the driver of a vehicle wants to make a trip from alocation A to B on a third Monday morning in September, the routeleading mostly through rural areas.

The desired trip is entered into the input unit 28 by reading, forinstance, a visiting card containing the origin node A and a furthervisiting card containing the destination node B, both visiting cardscontaining the geographical information in the form of bar-codes. It isunderstood that a numeric input or a voice input of the locations oforigin and destination are possible alternatives. It is advantageous toenter the origin and/or destination node by means of coordinates sincethis also permits to enter destinations for which either a postal codeor similar address is not available or not known to the system. Afurther advantage in addressing destinations by coordinates is that thesystem is able to direct the user to the closest identifiable point, ifa desired destination entered is not identifiable.

Since the intended trip is a route which the vehicle does not usuallyutilize, it is probable that no relevant information is available in thestorage units 40 to 48. Thus the input unit 28 will request a centralcomputer for relevant data for the desired trip, e.g. entering thedesired trip into the central computer 62 which either calculates aroute and sends back the resulting route data set, or just sends allrelevant data concerning the areas of origin and destination to thecontrol device 2 which will calculate the route. In both cases the datatransmission is charged to the requesting vehicle by the centralcomputer 62. This means that the request is only answered if specificvehicle data or a code identifying either the individual vehicle or thedriver has been entered. The full route is put together from theindividual section P_(j)P_(k) by using a well known optimizationalgorithm operating on the basis of the data in the section data file 72or the updated section data file 44 in such a way that, in the casewhere the trip takes place mostly in rural areas, the distance traveledis minimized. If the trip is mainly through municipal areas or, onexpress request by the driver, an optimization algorithm which minimizesthe total duration of travel time can be chosen. Other possibleoptimization criteria can be given, i.e. avoidance of road tolls ormountain passes, or minimization of fuel consumption, etc.

The recommended individual route sections are compared with the sectiondata already stored in the short-term storage units 46 or 74. The dataof the short-term storage units may suggest that the travel timeexpected under normal traffic conditions or normal state cannot berealized on a recommended route section. The display unit 30 shows thetrip route made up of the individual sections together with the expectedduration or arrival time. As the route is traveled the individualsections are identified so that route tips can be given continuously andthe location of the vehicle can be shown on a map. Deviations betweenthe route actually driven and the planned route can be corrected by thecomputer in the vehicle by calculating and displaying an updated routerecommendation.

In addition, the event storage unit 48 can be used if, for instance, itis necessary to refuel by requesting the location of a petrol station inthe relevant area. Alternatively, referral to an open petrol station canbe automatic and navigational help to find the station can be given.

As demonstrated above, the invention creates a system using modernsensor, computer, and storage technology to enable the optimal use ofthe available highway or route network, respectively, and to achievepredictable travel times, even in high traffic densities, by optimizingthe route.

The procedure for updating and merging data corresponding to theinvention's method is described below with reference to FIG. 3 to 10.

FIG. 3 shows a known route or road geometry in which the nodes 1 to 16represent road intersections and the links between these nodes representroads. This known road geometry can be stored either in the overallroute file storage unit 72 of the central computer 62 and/or in thesection data file storage units 44 installed in the mobile units orvehicles.

On the basis of this known route geometry or traversable road network,various cases will be described below.

In the first case, referring to FIG. 4 and based on the given routegeometry shown in FIG. 3, it is assumed that a first mobile unit, amotor vehicle for example, wishes to drive from the origin S, which liesat node 1, to a destination node Z which lies on node 16 of the givenroute geometry. Thus both the origin S and the destination Z are known.The central computer 62 or the optional data processing unit ormicroprocessor of the mobile unit recommend a route calculated on thebasis of the existing data material, i.e. the road geometry according toFIG. 3, taking into account travel times from a possible earlier trip ofthe same mobile unit or that of another mobile unit between the nodes Sand Z. The recommended route S→2→6→7→8→12→Z is represented by “x” inFIG. 4.

During the trip microprocessor 22 checks whether the mobile unit ismoving along the recommended route. It does so by using sensor 4 todetermine the location (i.e. GPS Receiver 4 in FIG. 1) and sensor 6 todetermine the direction of motion of the mobile unit (i.e. compass 6 inFIG. 1). Since the route is known it is not recorded again.

On the other hand, however, the travel time, i.e. the time of motion, ofthe first mobile unit is recorded. The pure travel time, i.e. the timeof motion of the mobile unit, and the total travel time, i.e. thedifference between departure time of the mobile unit at the origin S andarrival time at the destination Z, can vary due to stops at trafficlights, building works, etc. The distinction between the condition“motion of the mobile unit” and the condition “mobile unit isstationary” can be determined, for example, by means of an appropriatesensor, attached to a wheel or a shaft of the mobile unit, to measure orcount rotations. If an additional sensor is provided to measure the fillstate of the fuel tank of the mobile unit, the state “mobile unit isstationary while purchasing fuel” can be recorded and used whendetermining the total travel time. It is also possible to record thelocation of a petrol station, if this is not yet known, and transmitthis information to the central computer 62, along with the rest of thedata transmitted by the mobile unit so that this location informationcan be made available to other mobile units on the same route or in thesame area. Upon reaching the destination Z or after a predetermined timeperiod, the transmission device, i.e. the data input/output unit 32 inFIG. 1, transmits the data recorded by the first mobile unit duringmotion from the intermediate storage units 44, 46 and 48. This can bethe pure travel time, the total travel time, the start time of themobile unit, the weekday, the location of a petrol station, etc. If thefirst mobile unit is provided with the optional CPU 22, then this datacan be processed before being transmitted.

Data is received by the central computer 62 over its transceiver device,i.e. the transceiver unit 64 in FIG. 2, and processed and evaluated bythe CPU 66 of a central computer before being saved in the overall routefile storage unit 72 in accordance with the route taken between theorigin S and the destination Z, the weekday and start time as well asbeing scored with the pure travel time and/or the total travel time.Insofar as trip times for alternative routes from the origin S to thedestination Z in FIG. 4 are not yet known, if another mobile unit wishesto travel along the same route or has the same origin node anddestination node, the central computer 62 or the CPU 22 of the mobileunit will, upon transmission of said available data by the centralcomputer 62 to the CPU 22 of said mobile unit, will recommend the routeS→2→6→7→8→12→Z, since this route is the only one which has been recordedearlier with a realized trip time.

The case can now be considered where a second mobile unit, or the firstmobile unit described above, makes the same trip between the origin nodeS and the destination node Z in FIG. 4. However, in this case, themobile unit needs to travel over node 9 (for example because the driverof this mobile unit has to take care of some task on the road sectionbetween points 5 and 9 or between points 9 and 10). In such case it ispossible to enter this constraint together with the input of thedestination. The central computer 62 or the optional CPU 22 of themobile unit takes into account the constraint and recommends the routeS→5→9→10→11→15→Z. This route is marked with “o” in FIG. 4.

The absolute starting time of the trip of the mobile unit is againdetermined and saved. Once again the pure travel time along each sectionis recorded together with the total travel time. Since the recommendedroute is a component of the known road geometry, no recording of roadgeometry is carried out. Only the location and the direction of motionare checked by the corresponding sensors 4 and 6 to ensure that themobile unit actually moves along the suggested route. Recorded data issent by the transmission device 32 to the central computer 62 at the endof the journey or after a predetermined time period. The centralcomputer stores the transmitted data as outlined previously and scoresit with the pure travel time and/or total travel time. With regard tothe evaluation criterion “shortest travel time”, the individual routesare immediately comparable provided that the journey of the secondmobile unit has been executed at the same time of day, and on the sameweekday, as that of the first mobile unit. Assume that the routeS→2→6→7→8→12→Z has a shorter travel time (“pure” travel time or totaltravel time) than the route S→5→→9→10→11→15→Z, perhaps because thetraffic light switching of the second route mentioned is moreunfavorable or because the volume of traffic is higher on this routethan on the first one. In such case, either the central computer 62takes into account this result to send the assumed travel time for arecommended route to a mobile unit or it sends the evaluated result tothe CPU 22 of the mobile unit, which can then take into account theinformation independently. Thus a mobile unit making the trip from theorigin node S to the destination node Z in FIG. 4 on a specific weekdayat a specific time of day, on the basis of this evaluated result, candrive along the route with the minimum time.

It is self evident that on repeating this procedure with a large numberof mobile units within the framework of the road geometry, as shown inFIG. 3, favorable routes for other times of day and weekdays can bedetermined. It should be noted, in this context, that the storage ofroutes together with the trip times could be done by storing the routeas a whole or by storing the individual route segments and theircorresponding realized travel times. A substantially higher storagecapacity is needed for the last-mentioned method, but a far greaterflexibility is reached since a disturbance prolonging the travel timewithin a route does not require the recalculation of a complete routebut possibly only the recalculation of the one segment which needs to bereplaced. This case is explained below in detail.

In determining an optimal route with respect to travel time, thesituation can arise where a particular route is favorable on a specificweekday at a specific time of day, but unfavorable at another time ofday and/or weekday. Furthermore, it is self-evident that thesignificance and reliability of route recommendations increase with thenumber of trips made by mobile units in the road network depicted byFIG. 3. Thus, for a time-optimal route between the origin S and thedestination Z, highly differentiated route recommendations may be madefor different times of the day and days of the week.

Changes to the road geometry can also be taken into account. Forexample, Suppose that road work is commenced on the route S→2→6→7→8→12→Zbetween the points 6 and 7 which results in traffic congestion. Themethod in accordance with the invention takes into account this event byrecording an increase in the travel time on the route. Said increase intravel time would be transmitted to the central computer at the end ofthe trip. After a certain total number of measured travel times, saidnumber of samples being freely selectable as a function of the desiredstability of the result, the route would be newly evaluated by thecentral computer 62. Thus, in recommending a route, the new evaluationwould be taken into consideration by the central computer 62 or anoptional CPU 22 of a mobile unit, either by calculating a completely newroute (e.g. the route S→5→9→10→11→15→Z), or by making a modification tothe first route recommendation so that the route would now run:S→2→6→10→11→2→Z.

The destination tracking system or method in accordance with theinvention is not only able to determine a minimal time route fromseveral possible routes, depending on the time of day, day of week,etc., for a given road geometry and to update the route recommendationscontinuously but also to update the road geometry. This capability isexplained below.

It is assumed that a third mobile unit also wants to travel from theorigin S to the destination Z, with the road geometry of FIG. 3 and FIG.4 being known. The mobile unit, however, actually takes the routeS→6→11→Z, shown in FIG. 4 by the dotted line, due to the knowledge ofthe user. During this trip, the new road geometry will be recorded bythe mobile unit, in particular by means of sensors 4 and 6 which detectthe position and the direction of motion of the mobile unit, and thisinformation will then be transmitted to the central computer 62 at theend of the journey or after a predetermined time period. The centralcomputer 62 can now update its data stock with regard to the roadgeometry and also inform the CPU 22 of the mobile units. In recordingthis, until now, unknown route, the travel time is also recorded so thatthis route or its individual segments can be evaluated with regard tothe travel time and possibly recommended as a time optimal route.

A further case corresponding to FIG. 5 is examined below. It is assumedthat a mobile unit moves from the origin node S, which corresponds tonode 1, to a destination node Z outside the known road geometry and thusunknown to the navigational system. On the basis of the given roadgeometry, the central computer 62 or the optional CPU 22 of the mobileunit is unable to find a route to a node Z outside the known roadgeometry. However, upon entry of the coordinates of said destinationnode Z, the central computer 62 or the optional CPU 22 can identify node16 as the point nearest to the unknown node Z. Thus a routerecommendation is made which brings the mobile unit to a node directlyin the neighborhood of the node Z. This route might be S→6→11→16. Thisis possible as the new route found in connection with the case depictedin FIG. 4 is now known after merging the data representing thecorresponding road geometry. The mobile unit must now driveindependently from node 16 to the destination Z. This new path from node16 to destination Z is recorded and at least the new section is sent tothe central computer 62 at the end of the trip or after a predeterminedperiod of time. The central computer thus expands its data set. FIG. 6shows the road geometry known after such trip. The newly introduced nodeis labeled as 17.

Even though the user of the mobile unit would have to find the link ordestination node without the aid of the system according to theinvention, the system will, with a high degree of probability, be ableto lead the mobile unit back, e.g. to the starting point, due to therecording of the road geometry.

FIG. 7 depicts a case analogous to the previous case, but where thedestination node Z is known while the origin node S is unknown. Themobile unit commences its trip, at first without a recommended route,until it reaches a node that is known to the central computer 62 or itsoptional CPU 22. In the present case this is the node 2. It could justas well have been any other node such as 1, 3, 4, 5 or 9, etc. The routefrom the origin node S to the point 2 is recorded together with thetravel time. On reaching node 2, the central computer 62 or the optionalCPU 22 of the mobile unit is now able to recommend a route based on thecurrent updated database after merging the data resulting from theexamples in FIG. 5 and FIG. 6. This route could be the route2→3→7→11→16→Z. However, since the driver of the mobile unit knows that adirect geometric connection exists between nodes 2 and 7, he can takeadvantage of such knowledge when driving to node 7. The mobile unitrecords this new link in addition to the section already traversed bythe mobile unit between the origin node S and node 2. The mobile unitthen turns off the recording of road geometry after reaching node 7since it is traversing known route sections. However, determining andrecording of travel times and/or of the absolute times to reach a nodeare continued. The newly recorded road sections are transmitted to thecentral computer 62 either at the end of the trip or after apredetermined time period. The central computer evaluates the sectionsas to the trip times and stores them. The new road intersection islabeled as 18 in FIG. 8, which now reflects the new known road geometry.

This updated road geometry can now be provided to all mobile unitseither automatically or on demand.

A final case is shown in FIG. 9. The location of the origin node S andthe destination node Z are known. However, on his way to the destinationnode Z (i.e. node 17), the driver of the mobile unit wishes to visitnode 19 which lies outside the known road geometry. Since the connectionbetween the origin node S (node 18) and node 2 is known to the centralcomputer 62 or the optional CPU 22 of the mobile unit from the casedescribed with reference to FIG. 7 and FIG. 8, and, due to the entry ofthe coordinates of destination node 19, the system components 62 and/or22 also know that node 13 of the known road geometry is the pointclosest to node 19, and the recommended route might beS->2->6->10->9->13. The driver must find his own route from node 13 tonode 19 and back to node 13 or look for a new route, possibly over node14, or a direct route to the destination node Z. It is assumed that thedriver of the mobile unit is looking for a direct route to thedestination node Z and it is also assumed that a direct route betweenthe origin node S (node 18) and node 1 is known to the driver of themobile unit. The route between the origin node S and node 1, betweennode 13 and node 19, as well as between nodes 19 and Z is recorded bythe mobile unit and transmitted to the central computer 62 as describedabove. The transmitted data is evaluated as before and made available tothe mobile units. FIG. 10 represents the now known road geometryobtained by merging the data.

In contrast to known destination tracking methods or systems, the methodor system according to the invention continuously revises data withrespect to the traversable network sections as well as realized andrealizable trip times or times of motion, to calculate minimal timeroutes between two arbitrary nodes. This is achieved by merging new dataon links and traffic conditions that model reality into the system'sstorage units. Furthermore, the system or method according to theinvention, being based on the use of coordinates, can lead a mobile unitto a node close to the desired location even when this location is notaccessible on the basis of the road geometry known to the system.

In conclusion, it is taken for granted that the term “mobile unit” canapply to any type of vehicle as well as to pedestrians who are equippedwith a portable appliance which exhibits the same constructionalfeatures as those discussed above.

What is claimed is:
 1. A method for generating and updating data for usein a destination tracking system of at least one mobile unit comprising:generating and storing traveled distance data in at least one storagedevice provided in said mobile unit at least at predetermined timeintervals, wherein the traveled distance data represent traveledsections by at least a series of nodes P_(i) and to each node P_(i)geographical coordinates x_(i) and y_(i) are assigned; generating andstoring section data in the storage device provided in the mobile unit,said section data being generated by selecting, from the traveleddistance data, nodes P_(j) and P_(k), which define contiguous sectionsP_(j)P_(k), to which at least their geographical starting point and endpoint are assigned; and generating a section data file from the sectiondata and storing the section data file in the storage device provided inthe mobile unit, said section data file being continuously supplementedand/or updated with section data newly generated by the mobile unit. 2.The method according to claim 1, further comprising the steps ofmeasuring and recording as section data a direction of motion ∝_(i) ofthe mobile unit, in addition to measuring and recording the geographicalcoordinates x_(i), y_(i) of the nodes P_(i) of the traveled distancedata.
 3. The method according to claim 2, further comprising the step ofderiving the direction of motion ∝_(i) from the geographical coordinatesx_(i), y_(i) of the nodes P_(i) of the traveled distance data.
 4. Themethod according to claim 2, further comprising the step of detectingthe direction of movement ∝_(i) by means of at least one sensor providedin the mobile unit.
 5. The method according to claim 1, furthercomprising the steps of interrupting the generation of section data inthe mobile unit if the section data being generated are already storedin the storage device of the mobile unit and restarting the generationof data if the section data are not yet stored in the storage device ofthe mobile unit.
 6. The method according to claim 1, further comprisingthe steps of preparing, via a data-processing device provided in themobile unit, if requested by inputting at least a destination point intoan input device provided in the mobile unit, a recommended route from aroute data file already available in the storage device of the mobileunit, and representing said recommended route visually and/oracoustically in the mobile unit.
 7. The method according to claim 6,further comprising the steps of utilizing, in the event either or bothof the starting point and destination point are unknown, the dataprocessing unit provided in the mobile unit or a central computer forprocessing either or both of the nearest known starting point and/ordestination point from the section data file stored in the mobile unitor from the at least one overall route file stored in the centralcomputer to calculate a recommended route.
 8. The method according toclaim 6, further comprising the step of using coordinates to specify thestarting point, the destination point, and/or another point lyingbetween the starting point and the destination point.
 9. The methodaccording to claim 8, wherein the coordinates are represented by abar-code.
 10. The method according to claim 6, further comprising thestep of restarting the generation of the traveled distance data by themobile unit when the mobile unit takes a route not recommended by acentral computer or by a data-processing device of the mobile unit. 11.The method according to claim 1, further comprising the steps oftransmitting the section data files of more than one mobile unit to atleast one central computer located in a location remote from said atleast one mobile unit and having said central computer merge saidsection data files at least at predetermined time intervals into atleast one overall route file.
 12. The method according to claim 11,further comprising the steps of having said central computer check thefile transmitted by a mobile unit for its update value before mergingsaid file with the section data files and only merging said file with anoverall route file if said file contains at least partially newinformation.
 13. The method according to claim 11, further comprisingthe steps of adding a characteristic classifying each mobile unit to thefiles transmitted by said mobile unit, and generating via a centralcomputer different overall route files corresponding to the differentcharacteristics.
 14. The method according to claim 11, furthercomprising the steps of adding an identification code identifying themobile unit to the data transmitted by the mobile units and detecting,via a central computer, the update value of the data transmittedtogether with the identification code of the mobile unit for calculatinga reimbursement fee for each mobile unit transmitting data.
 15. Themethod according to claim 11, further comprising the step oftransmitting the section data file generated by a mobile unitimmediately after motion of the mobile unit terminates.
 16. The methodaccording to claim 11, further comprising the step of transmitting thesection data file generated by a mobile unit to a central computer aftera predetermined time interval.
 17. The method according to claim 11,further comprising the step of transmitting via a central computer atleast one overall route file to the mobile units according topredetermined criteria.
 18. The method according to claim 17, furthercomprising the step of transmitting the overall route file automaticallyto the mobile units, preferably after a predetermined time interval. 19.The method according to claim 17, further comprising the step oftransmitting the overall route file via a central computer to a mobileunit upon a request by the mobile unit.
 20. The method according toclaim 11, further comprising the steps of preparing and transmitting toa mobile unit, via a central computer, a recommended route calculated onthe basis of the at least one overall route file stored in the centralcomputer, if said central computer is so requested by said mobile unit,by transmitting at least a destination point.
 21. The method accordingto claim 1, further comprising the step of terminating generation of thetraveled distance data if motion of the mobile unit ceases.
 22. Themethod according to claim 1, further comprising the step of determiningabsolute coordinates of the mobile unit using the Global PositioningSystem.
 23. The method according to claim 1, further comprising thesteps of recording and storing a time T_(i) of arrival at a node P_(i)of the traveled distance data in addition to recording and storinggeographical coordinates x_(i), y_(i) in the storage device of themobile unit.
 24. The method according to claim 1, further comprising thesteps of assigning and storing an absolute time of motion T_(jk) to thesections P_(j)P_(k) of the traveled distance data.
 25. The methodaccording to claim 24, further comprising the step of suppressingduration of non-movement of the mobile unit when determining theduration of motion t_(jk).
 26. The method according to claim 24, furthercomprising the steps of averaging the section data with respect to timeof day, day of week, position of the day in the month, and the month andstoring computed averages together with the frequency distribution ofthe durations of motion t_(jk).
 27. The method according to claim 24,further comprising the steps of saving, in a short term section datafile stored in a short term storage device of said mobile unit, the mostrecent section data, said short term section data file containingactually realized durations of motions t_(jk) relating to individualsection data for a short past period.
 28. The method according to claim1, further comprising the steps of assigning and storing an actualduration of motion t_(jk) to the sections P_(j)P_(k) of the traveleddistance data.
 29. The method according to claim 28, further comprisingthe step of aggregating geographically identical sections of differentmotions of the mobile unit for predetermined time intervals of aduration of motion t_(jk) in the section data file.
 30. The methodaccording to claim 28, further comprising the step of calculating meanvalues from the durations of motion t_(jk).
 31. The method according toclaim 28, further comprising the steps of calculating a frequencydistribution of the durations of motions t_(jk) for periods which areidentical to typical traffic conditions and assigning said frequencydistribution to the section data P_(j)P_(k).
 32. The method according toclaim 1, further comprising the step of determining the nodes P_(j)P_(k)of a section P_(j)P_(k) in accordance with the occurrence of a change indirection.
 33. The method, according to claim 1, further comprising thestep of determining nodes P_(j)P_(k) of a section P_(j)P_(k) so thatsaid nodes lie at the intersection of sections running in differentdirections.
 34. The method according to claim 1, further comprising thestep of storing supplementary data, said data comprising at leastperiods of non movement of the mobile unit, in the section data.
 35. Themethod according to claim 1, further comprising the steps of determiningand saving the data within a vehicle representing a mobile unit.
 36. Amethod for deriving destination tracking data from the data generated inaccordance with claim 1, comprising: requesting a desired trip from acomputer with knowledge of a section file; specifying said desired tripby inputting a starting point, a destination point, a starting or targettime, and any special requirements; calculating via said computer aroute composed of individual sections using the section file andminimizing the duration of motion or the route length taking intoaccount any special requirements; and displaying the relevant dataderived from the route determined as described above in a display unitand/or outputting said data acoustically.
 37. The method in accordancewith claim 36, further comprising the step of using, when the computercalculates a route, the most recent section data stored in the shortterm section file together with the corresponding section data from thesection file which does not deviate typically from the correspondingrecent section data.
 38. A device for carrying out the method accordingto claim 1, for use in at least one mobile unit comprising: a locationsensor to determine the current geographical position of the mobileunit; a milometer to generate a route signal corresponding to traveleddistance; an input unit; a display unit; and an electronic controldevice containing a microprocessor, a ROM and a RAM, said control devicecomprising: a motion storage unit; a section storage unit; and a sectiondata file storage unit; said location sensor, said milometer, said inputunit and said electronic control device being electrically connected tocarry out said method.
 39. The device according to claim 38 furthercomprising a short term section storage unit.
 40. The device accordingto claim 39, further comprising a direction sensor provided to determinethe current geographical direction of the mobile unit.
 41. The deviceaccording to claim 38, further comprising a clock provided to generatetime signals.
 42. The device according to claim 38, wherein the inputunit comprises a read unit to read an address information as adestination point from a data carrier.
 43. The device according to claim42, wherein said read unit is a facility for reading bar-codes.
 44. Thedevice according to claim 38, further comprising a transmission devicebuilt into the mobile unit for transmitting collected data and a centralcomputer installed in a remote location from the mobile unit, saidcomputer receiving and evaluating the data transmitted by thetransmission device of the mobile unit and thereafter storing theevaluated data.
 45. The device according to claim 44, wherein areceiving unit of the transmission device receives data from a centralcomputer and an output device of the mobile unit outputs the datareceived from a central computer.
 46. The device according to claim 44,wherein the transmission device contains an interface.
 47. The deviceaccording to claim 44, wherein the transmission device contains a radiodevice.
 48. The device according to claim 38, further comprising arecording device for recording the time of starting and ending of amotion and/or the day of the week on which the mobile unit is moved. 49.The device according to claim 38, further comprising a revolutiondetector for detecting the revolutions of a motor when said device isinstalled in a motor driven mobile unit.
 50. The device according toclaim 38, further comprising a fuel level detector for detecting thefuel level of a motor driven vehicle when said device is installed insaid vehicle.
 51. The device according to claim 38, wherein saiddirection sensor is a gyrometer and/or a compass.
 52. The deviceaccording to claim 38, further comprising a Global Positioning Systemreceiver for detecting a current absolute position of the mobile unit.53. The device according to claim 43, wherein a central computer is partof a stationary navigational unit which in addition to the centralcomputer contains a transmission device to receive and send data fromand to a mobile unit and contains at least one storage unit.